Dross must be removed from the coating bath used in a galvanizing operation to prevent the formation of imperfections in the coating that might otherwise take place if impurities floating on the molten pool or sunk to the bottom were to deposit out in the coating. The collection of dross to remove it from the bath and subsequent pressing of the dross to remove molten metal entrained therewith is known generally as shown in the U.S. Pat. No. 2,278,135 to Osborn, Mar. 31, 1942. In this patent, dross is lifted in baskets that dip into a molten metal bath and any molten metal entrained with the dross is freed by pressing the dross with flat headed pistons in closed cylinders to free some of the entrained molten metal that flows back into the larger molten bath of metal while the cylindrical press cakes formed of the solid dross and some of the retained molten metal are removed on suitable collection platforms for further treatment by higher pressure or chemical treatment or are simply held in storage for subsequent refinement to recover the valuable metal component thereof.
Also, it is known to remove entrained molten metal from metal slags or dross by agitating the slag with stirring rods as described in U.S. Pat. No. 1,559,803 to Stout, Nov. 3, 1925. This particular disclosure is concerned with removing molten metal from slag by contacting iron bars having a relatively high melting point, with copper slag for example, that has a melting point lower than that of the iron bars to procedure a reaction with the exposed surfaces of the bars and certain ingredients of the slag to precipitate copper from the slag. The molten copper that is released in the material being agitated, precipitates out to settle to the bottom of the container holding the slag, to be drawn off, the desired copper precipitating reaction is expedited by agitating the iron rods throughout the body of slag.